hammon



April 19,1932. H HAMMON Re. 18,427

SPECTACLE LENs originalFiled April e. 1927 ATT ORNE V5.

ReissueclA Apr. 19,

.IAIIEs II. IIA'InIoN, or VINCENNES, INDIANA SPECTACLE LENS Original No. 1,740,298, dated December 17, 1929, Serial No. 181,557, led April 8,1927. Application forl reissue led October 17, 1980. Serial No. 489,468.

My invention relates to multi-focal spectacle lenses, and has for its object to produce a Spectacle-lens for those people who require different correction for distance and for near Q vision, in lenses having continuous front and back surfaces, and the bifocal side has an uninterrupted curvature.

My improvement consists in making such continuous surfaced lenses so that the user, when looking though them and changing from distant to near vision and'vice Versa, shall se'e no apparent displacement or jump of the object-viewed. ,f

My improvement further consists in making the portion used for near vision a prism whose base or thicker portion isv directed to-.

ward the center of the lens.

I shall explain my invention with reference to the drawings, 111 which like parts are similarly designated and in which-' Figure 1 is an elevation illustrating av spectacle lens such as used by paper hangers and others who require near :vision both when looking up and down. Fig. 2 is a. section on line 2-2 of Fig. 1,

Fig. 3 shows the button. Fig. 4 the major portion of the blank having a perforation in which the button fits.

Fig. 5 is a section showing the button fused in the perforation and the lower face of the compound portion surfaced .and polished.

Fig. 6 is `a section showing the major portion and button superimposed on a third spherical surface of proper curvature preparatory for-fusing. l

Fig. 7 is a cross section of av fused or rough blank. i i

Fig. 8 is across section of a blank after olishingq one surface to form a semi-finished lank.

Fig. 9 shows where the opposite surface is vto be cut by the optician. y

The detalls of my process are preferably as follows;

I first take a piece of crown glass a or the v like that is to form a part of the main por-- tion of the lens blank, perforate or make a hole b in it and lish the walls thereof. I then insert in t perforation b what. is 5 termed in the trade a button c whose sides are preferably polished. This button c has a dilferent index of refraction thanthe piece a. They may then be fused together by the vwell known method of fusing or otherwise.

.I then heat the glass to soften -it and press or mold this compound portion into one piece to approximate or desired shape, and polish one face, as the face d in Fig. 5, which preferably but not necessarily is of'les'serv radius than a third or cover portion e of theblank.

The cover'portion e of the blank is a glass having preferably the same index of refraction as the crown portion or approximately the-same, and its .one surface f is ground and polished to the proper'surface or curvature for giving to the surface of the button that shape or curvature required by oneend m of the button that is to be covered bythe portion e. v

The assemblage is then fused together, producing the composite piece of fused glass illustrated in Fig. 7. From this composite piece the rough.blank is ground along a line, as g-g for example, to the proper curvature or diopter for .one face of the commercial or semi-finished blank, and this face is then polished, giving one polished face It of con-A tinuous or unbroken surface and leaving a portion of the button c whose one face m is covered by the glass of the portion 'o and its thicker portion or base i is directed toward the center or geometrical axis k--c of-the finished lens to be ground vfrom such blank.

In this form the blank isv sold to the optician who, knowing or being informed of the power or diopter of both the prism c and polished surface h, then, according to technical directions, grinds and polishes the other l surface of the blank to that dioptric curve that when combined-with'the dioptric curve' or curves of the other surface, as h, gives the requiredcorrection and proper location vof optical centers for the wearer `of the spectacles. A.

By such a construction all the surfaces of the lens, i. e., front and rear surfaces of the prism c', may have a common' axis, as -w in Fig. 2. This will, ,of course', be so in all cases except when the one face of the prism c is a plane, in which case its plane or lot l Vvside w-ill'be at right angles to this axis, ,but

the thicker base -i will in all cases be directed 'toward' the center of .the finished lens.

Ofcourse, it is understood that what opticians undelstand to be -av prism may have curved or spherical surfaces, orflat surfaces or both flat and curved surfaces; in other Words, it may be considered a sort of lens in which the geometrical and optical centers of theA prism do not coincide.

The invention claimed is: V

1. A multi-focal fused spectacle lens having a major perforated portion surrounding a fused insert portion and both fused t-o a third portlon of substantially the same kind of glassas thel major `perforated portion, said insert portion forming a prism having the sameY cross sectional area as 'the perforation covered by the third portion.

2. A'multi-focal fused spectacle lens having a ma-jor perforated portion and a fused the area of the insert" portion of the same cross section as the perforation.

, V3. Aniulti-focal fused spectacle lens having'v a major perforated portionl and a fused "insert `portion bothA groundand polished and a third portion fused thereto ground-and polished to the required surface and of substantially theV same glass as the major perforated portion, said insert portion forming a prism covered by the third portion and surrounded by the major perforation portion,

andthe outer exposed face of said prism conforming to the outer surface of the lens and of the sarge area asthe cross section of the A perforation.

4. A multi-focal fused spectacle lens having a major perforated portion surrounding s a fused insert-I portion and fused thereto, a

.. tour third portion covering theV insert portion,

said-insert portion forming a; prism Whose base is directed towardthe centre ofthe lens and whose outline is determinedV by and of the same size as the perforation. Y 5. AV multi-focal spectacle lens vhaving' la major perforation portion, and a prism inserted in and surrounded by said portion having its basetoward the centre of the lens and having oe face concentric withl the face o f the Vdens, 'andi afcovering for the prism of substantially 'the sameindex of refraction asl said major portionf'andjthe outline of said insert portion determined as to size and conl ,l the"IJe'rforatioli.-'` .1

' being finished.

having a button fused in a perforation therein ofprismatic shape with the base toward the centre of the blank, said blank having one continuous ground and polished surface including the button and theA opposite face of the blank fused to a layer of glass that covers the button. i

7. The method o-f making a4 fused multifocal lens, whi ch comprises fusing a button in an opening through a portion of a blank to form a composite blank, grinding and polishing a companion blank to the desired surface, fusing4 the composite blank onto the polished surface of the companion blank so as to cover the button, and forming a lens from the blank.

8.' The methodof making a fused multifocal lens, which comprises fusing a polished button in anA opening through a portion of a blank to form a composite blank, pressing the -composite blank to approximate surface curvature and grinding and polishing one face of the composite blank, fusing the polished face of the composite blank to a pol-A ished surface 'of a companion blank Whose polished face-has the surface desired.

9. A multi-focal fused. spectacle blank 1 having a major portion havinga perforation therethrough with straight Walls from end to end thereof, a button-corresponding in shape to said perforation and fittedand fused4 therein, va companion blank to which one face of `said major button portion is fused and the opposite face of said major'portion 10. A multi-focal fused spectacle lens having a major portion with a perforation therethrough having different rectangular dimen` sions 1n cross section and an inserted portion `fusedin the perforation, a companion glass to which said major portion and inserted portion are fused and of the same kind of glass as the major portion. 1 1. `The method of making a'fused multifocal vlens, which comprises fitting a button of one index of refraction into a perforation in Aa major blank-of a different index of refraction, fusing the button into the blank, grinding the lower face of the blank to give thel end of the button a proper curvature, fusing the ground surfaceto a glass, andgrindig and polishing the exposed face of the major blank including lthe exposed face .of the button, said button determining the size and-shape of the insert portion of the fmished lens.

l '12. In a method for the manufacture of a. i

fused bifocal lens blank which comprises fusing onto a major lens in one side of which v has been ground a depression or like surface,

index as thefmajor lensp1acing an insert, of glass ofa different refractivevindex in said 4 hole, and then fusing the insert to the segment.

- 13. A method for the manufacture of a fused bifocal lens blank which consists in forming a iece of glass with one face thereof surfaced, orming a compound segment consisting of a piece of glass of the same refractive index as said first-mentioned piece of glass With an insert-receiving hole in it, fusing an inserted piece of glass of different refractive index in said hole, surfacing one side of said compound segment to substantially the opposite curvature of the surfaced portion of said first-mentioned piece of glass, and then fusing said compound segment uponl the surfaced portion of said first-mentioned piece of glass.

14. A method for the manufacture of a fused bifocal lens blank which consists in forming a piece of glass with one face thereof surfaced, forming a compound segment 'consisting of a piece of glass of the same refractive index as said first-mentioned piece of glass with an insert-receiving hole in it, fusing an inserted piece of glass of different refractive index in said hole, surfacing one side of said compound segment to substantially the opposite curvature of the surfaced portion of said first-mentioned piece of glass,

fusing said compound segment upon the sur-` faced portion 'of said first-mentioned piece of glass, and then providing` a final bifoeal surface cutting all of said pieces of glass, substantially as set forth.

15. In the method of making a multifocal fused lens, providing a hole in a piece of glass `of one index of refraction, fusing a minor insert portion of a different lindex of refraction 1n said first-mentioned portion of glass so as to be entirely-surrounded thereby, surfacing one side of the compound piece of glass'so as to shape the inner face of the minor insertportion, surfacing one side of athird piece of glassand fusing said compound piece of glass upon the surfaced portion of said third piece of glass.

16. In the method of making a multifocal fused lens, providing a hole in a piece of glass of one index of refraction, fusing apminor insert portion ofa different index of refraction in said first-mentioned portion of glass so as tbe entirely surrounded thereby, surfacing one side of the compound piece-of glass/so as to shape the inner face of the minor insert portion, surfacing; one side of a third piece of glass, fusing said compound piece of glass upon .the surfaced portion of said third piece of glass, and then grinding away some of the exposed parts of said .compound piece of glass so as to provide the iinished lens with a continuous uninterrupted curvature on the bifocal side.

17. `A multi-focal fused spectacle lenshaving. a major portionv .made Vof glass of one index of refraction suitable for distance v1- Sion, and a minor portion made of glass of a different index of refraction suitable for near vision. embedded in, covered on one side and surrounded by said major portion and having a peripheral Wall around it substantially perpendicular to the surface of the lens, and

each side of said lens having' a continuous a continuous peripheral Wall substantially perpendicular to the surface of the lens, and a minor portion of glass having a different index of refraction'suitable for near vision imbeddedV and fused in said hole, and the bifocal side of said lens With the exposed surface of said minor and major portions of the lens having one continuous .uninterrupted curvature with the minor portion surrounded and covered on 011e side by the said major portion.

19. A multi-focal fused spectacle lens formed With the major portion of glass having one index of refraction suitable for distance vision and a hole in one side thereof with its 'Width greater than its length and having a peripheral Wall substantiallyperpendicular to the surface of the lens, and a minor portionvcomposed-of glass of a diEe-rent index of refraction imbedded and fused in said hole and conforming in shape thereto andcovered on one side thereby, and the bifocal side ofsa-id lens being surfaced throughout With a continuous uninterrupted curvature including the exposed surface of said minor portion of the lens.- y

20. A multi-focal fused spectacle lens having a major portion formed of glass of one index of refraction With a hole formed in one side thereof the peripheral Wall yof which is substantially perpendicular to the surface of the lens, a minor portion of glass made of a different index'of refraction suitable for near the same curvature as the bottoml of the hole and imbedded and fused therein, one side of the minor portion being covered by the, said major portion, and each side surface of said lens having a continuous uninterrupted cur-- vature including the exposed surface .of said minor portion, whereby the optical center of said minor or near vision portion can be predetermined in' the manufacture of the lens.

In witness whereof, I have hereunto affixed my signature.

JAMES H. HAMMON. 'us 

